A low-voltage low-power injection-locked RF oscillator using a selfcascode structure and body terminal coupling is reported. A selfcascode structure facilitates higher resistance in each conducting path and helps achieve low-power operation without degrading the voltage headroom. Body terminal coupling provides injectionlocking without appreciably increasing the power consumption. The proposed oscillator fabricated in 0.18 mm RF CMOS process can operate with a supply voltage as low as 0.9 V and consumes only 1.161 mW of power for 1.30 GHz operating frequency. Relatively low power consumption makes the design highly suitable for lowpower transmitter applications.Introduction: Power consumption of the transmitter unit typically dominates the power consumption of the sensor nodes in a wireless sensor network (WSN) or wireless body area network (WBAN). Unlike conventional transmitters used for cellular applications, the injectionlocked transmitter (ILTX) shows greater promise with low power and high efficiency for short-range wireless communication. An RF MEMS-based injection-locked power oscillator-based transmitter has been reported [1], which achieved a drain efficiency of 32% at 0 dBm output power from a 280 mV supply while operating at 1.9 GHz.The core block of an ILTX is usually an injection-locked oscillator (ILO). In this deep submicron CMOS era, it is necessary to develop both low-voltage and low-power circuits to accommodate low supply voltage and higher threshold voltage features for mixed signal environments. Therefore, in this Letter a low-voltage low-power (LVLP) ILO is proposed employing a self-cascode structure and body terminal coupling. To overcome potential frequency interference problems due to the widespread use of industrial, scientific, and medical (ISM) frequency bands, the Federal Communications Commission (FCC) approved wireless medical telemetry service (WMTS) bands (608-614 MHz, 1395-1400 MHz and 1429 -1432 MHz) have been used for the design of the aforementioned LVLP oscillator. Self-cascode structures have been used extensively [2] for low-frequency analogue circuit design but rarely for high-frequency oscillator design. Incorporation of the selfcascode structure in the proposed design provides higher output resistance in each conducting path without degrading the voltage headroom. Unlike the tail-MOSFET injection and the direct injection structures, the body terminal coupling helps achieve injection-locking without significantly increasing the power consumption. Measurement results indicate that the proposed oscillator can work with a supply voltage as low as 0.9 V with a power consumption of 1.161 mW for an operating frequency of 1.30 GHz.
